Another frustrating day....
Turbo Mini Forums

OK Rod just went in garrage and checked a 1275 A block and it was 3/8 UNFP and checked a 1275 MPI block this was 3/8 BSP 28TPI. I also checked a MPI presure sensor and it was 28tpi 3/8 bspt.

Paul, I assume you have a typo and the 28 TPI ones were 1/8" BSP (not 3/8) but if you have at least one early A plus block that is 3/8" UNF(P) at 24 TPI, at least I am not alone.......

Schrödinger's cat - so which one am I ???

Checked the Zues book earlier and 3/8 UNF is 19 TPI & a 3/8 BSP is 24 TPI which is the same as 3/8 gas.

So at some stage your block has been re tapped to take a 3/8 UNF thread. I neglected to check the tapping drill size's but would guess the UNF is larger.

Own the day

No, 3/8 UNF is 24 TPI.

1/8 BSP - which has virtually the same outside diameter os a 3/8" UNF bolt - is 28 TPI.

Bolts (ie, 3/8 UNF) are measured on their outside diameter,
pipes (ie, 1/8 BSP) are based on a "nominal" inside diameter so the outside diameter is much larger than the title suggests.

A 1/8" BSP pipe has a similar outside diameter to a 3/8" UNF bolt.

It's then just the TPIs that are different.

Schrödinger's cat - so which one am I ???

oops! yes got that turned around UNF 24 BSP 19

Own the day

3/8 UNF 24 T.P.I. requires a 8.5mm drill where as an 1/8 BSP 28 T.P.I. requires a 8.75mm drill.

Not enough material to re tap either.

Own the day

Sorry Rod I typed that on my Blackberry and was to much effort to edit yes I ment 1/8 BSP(P) Ill edit later when I get back to office

Who on here was after the banjo bolt for the braided oil feed pipe assembly for a T3 turbo. I picked one up from Beachgrove eng. for Rod S but he informs me it was not he asking for one.

I also picked up 2 copper compessable washers for it as well.

Edited by Mr Joshua on 14th Jul, 2009.

Own the day

Thought you were after the standard one?

Good thing I asked i'd better swap it before he sends it.

Own the day

Yep, we have the braided hose sat waiting.